(1) Field of the Invention
The present invention relates generally to valves, and, more particularly, this invention relates to a two way pressure relief valve for reducing pressure differentials across surfaces.
(2) Description of the Prior Art
Modern submarines need the capability to launch torpedoes while underway. These undersea craft usually have fairing-like structures that cover the torpedo tubes to reduce turbulence and associated hull generated noise. The structures are removed before torpedoes can be launched. The mechanisms required to move the structures may be too heavy and bulky if they must not only move the weight of the structure but also overcome the pressure created across the sides of the structures due to hydrodynamic flow over the structure""s surfaces.
Thus, in accordance with this inventive concept, a need has been recognized in the state of the art for an apparatus for equalizing pressures and reducing the total force needed to open shutters covering torpedo tubes so that torpedoes may be launched while underway.
An object of the invention is to provide a valve for reducing pressure between faces of a surface.
Another object of the invention is to provide an inexpensive valve that can be operated in two directions.
Yet another object of the invention is to provide a valve that operates automatically when pressure between faces of the surface exceeds a predetermined tolerance.
These and other objects of the invention will become more readily apparent from the ensuing specification when taken in conjunction with the appended claims.
Accordingly, the present invention provides a two way pressure relief valve for equalizing pressure between a first region and a second region. The valve has a housing with a lateral aperture in communication with the second region and a first aperture in communication between the first region and the lateral aperture. A piston assembly having an annular rim portion is retained slidably within the housing. Flutes are formed in the piston assembly for allowing fluid communication between the first region and the second region. An annular retaining piece having a second aperture therein is joined within the lateral aperture in the housing at the second region for retaining the piston assembly within the housing. A first biasing means is positioned in the housing between the first aperture and the piston assembly for biasing the piston assembly away from the first aperture. A second biasing means is positioned in the housing between the retaining piece and the piston for biasing the piston assembly away from the second region. The piston assembly prevents flow through the housing during normal operations. If a sufficient pressure differential exists between first region and second region, the piston assembly slides in the housing allowing communication through the first aperture, flutes, lateral aperture and second aperture.